A conventional bicycle braking device comprising a brake lever and brake means operated thereby, is disclosed in Japanese Utility Model Publication Gazette No. Sho 55-23,009. Such braking device is provided between a pair of brake arms of, for example, a caliper brake, with a brake spring which restores the brake arms from the operating positions thereof to the original rest positions after the brake lever is released, by the cyclist the brake lever being restored from the operating position to the original position through the control wire connecting the brake arms and brake lever.
In brief, all heretofore known conventional braking devices have been provided at the brake means only with a brake spring for restoration so as to restore the actuating members, such as the brake arms, and also the brake lever.
The brake spring for lever restoration, in consideration of deterioration of a transmission efficiency of the control wire after long use, has a large spring force (usually approximately 4 kg) to restore the brake lever from the actuating position thereof to the original position.
Hence, a brake spring of having a large spring force as described above, is heavy to operate even when the control wire has a proper transmission efficiency .lambda.W, and moreover becomes further heavier when the efficiency .lambda.W is deteriorated.